The prior art related to printing and typewriting equipment includes various examples of linespacing mechanisms including: U.S. Pat. No. 1,469,776 to M. C. Crawley, U.S. Pat. No. 1,861,975 to R. E. Page and U.S. Pat. No. 2,777,559 to L. E. Tapp. U.S. Pat. No. 1,469,776 shows a linespace mechanism which has a friction clutch located between a motor and a linespace linkage. U.S. Pat. No. 1,861,975 shows a linespace mechanism which has a first cam with a continuous cam track for driving a linespace linkage. The linespace mechanism also includes a second cam and the linespace linkage may be driven by either cam. The cams are operated alternatively depending on the amount of linespacing desired. U.S. Pat. No. 2,777,559 shows a linespace mechanism which has a cam for driving a linespace linkage. The cam has a follower whose position relative to the axis of the cam may be varied in order to vary the amount that the roller is displaced during each turn of the cam.
Each of the above devices may be characterized as having a relatively high degree of complexity and comprising a relatively large number of component parts. This results in an overall high cost of ownership due to the relatively high initial costs which result from a need for careful, close tolerance, manufacturing techniques and complex assembly procedures and the relatively high maintenance costs which result from a need for frequent maintenance and adjustment procedures.